This invention relates to a method and an instrument for measuring the extensibility or pliability of tissue of the uterine cervix. More particularly, this invention relates to a method and an instrument for measuring the condition of the uterine cervix by means of applying a compressive force to the tissue of the cervix and measuring the tissue displacement resulting from the application of the compressive force.
The uterine cervix is both an active participant in the childbirth process and an important indicator of the physical preparation of the mother for childbirth. During the period preceding childbirth, the cervix normally undergoes a maturation process which is closely related to changes in the uterine muscle at the initiation of labor. Throughout labor, the uterine cervix undergoes a transition (including softening, thinning and dilation) some of which can be measured by various methods.
Prior instruments directed to quantifying the physical characteristics of the uterine cervix have been primarily directed to measurement of the dilation of the cervix during labor. Such instruments essentially measure the diameter of the cervical opening. While there can be little doubt that the measurement of dilation is a general indicator of the condition of the uterine cervix during labor, a more fundamental characteristic of the condition of the uterine cervix is the pliability or extensibility of the cervical tissue. This invention is based on the principle that changes in compressibility and extensibility of the cervix are related, as they are results of the underlying biochemical processes in the cervix. Thus, the ratio of the applied force to the tissue displacement represents a quantity indicative of tissue extensibility.
Prior related instruments have not provided for continuous monitoring of the cervix preceding and during labor. The present invention is directed to measuring changes of the uterine cervix throughout the labor process without requiring multiple vaginal examinations by an individual who monitors and supervises the cervical effacement (thinning) process. The present invention is not only capable of continuous monitoring, but it is capable of producing a more comprehensive and analytical picture of the condition of the uterine cervix and transmitting the information to a central monitoring facility (e.g. nursing station in hospital).
It is noted that the present invention may be employed in connection with a wide range of obstetrical and gynecological conditions such as premature labor, infertility, endocrine disorders and tumors. The invention is also applicable for use in connection with tissues other than the cervix, such as tissue of the ear or skin, and may be used in many non-obstetrical/gynecological applications.